Hypersensitive response induced resistance in plants

ABSTRACT

The present invention relates to a method of imparting pathogen resistance to plants. This involves applying a hypersensitive response elicitor polypeptide or protein in a non-infectious form to a plant under conditions where the polypeptide or protein contacts cells of the plant. The present invention is also directed to a pathogen resistant plant and a composition for imparting pathogen resistance to plants.

This invention was made with support from the U.S. Government under USDA NRI Competitive Research Grant No. 91-37303-6430.

This is a division of application Ser. No. 08/475,775, filed on Jun. 7, 1995 now abandoned.

FIELD OF THE INVENTION

The present invention relates to imparting hypersensitive response induced resistance to plants.

BACKGROUND OF THE INVENTION

Living organisms have evolved a complex array of biochemical pathways that enable them to recognize and respond to signals from the environment. These pathways include receptor organs, hormones, second messengers, and enzymatic modifications. At present, little is known about the signal transduction pathways that are activated during a plant's response to attack by a pathogen, although this knowledge is central to an understanding of disease susceptibility and resistance. A common form of plant resistance is the restriction of pathogen proliferation to a small zone surrounding the site of infection. In many cases, this restriction is accompanied by localized death (i.e., necrosis) of host tissues. Together, pathogen restriction and local tissue necrosis characterize the hypersensitive response. In addition to local defense responses, many plants respond to infection by activating defenses in uninfected parts of the plant. As a result, the entire plant is more resistant to a secondary infection. This systemic acquired resistance can persist for several weeks or more (R. E. F. Matthews, Plant Virology (Academic Press, New York, ed. 2, 1981)) and often confers cross-resistance to unrelated pathogens (J. Kuc, in Innovative Approaches to Plant Disease Control, I. Chet, Ed. (Wiley, New York, 1987), pp. 255-274, which is hereby incorporated by reference).

Expression of systemic acquired resistance is associated with the failure of normally virulent pathogens to ingress the immunized tissue (Kuc, J., "Induced Immunity to Plant Disease," Bioscience, 32:854-856 (1982), which is hereby incorporated by reference). Establishment of systemic acquired resistance is correlated with systemic increases in cell wall hydroxyproline levels and peroxidase activity (Smith, J. A., et al., "Comparative Study of Acidic Peroxidases Associated with Induced Resistance in Cucumber, Muskmelon and Watermelon," Physiol. Mol. Plant Pathol. 14:329-338 (1988), which is hereby incorporated by reference) and with the expression of a set of nine families of so-called systemic acquired resistance gene (Ward, E. R., et al., "Coordinate Gene Activity in Response to Agents that Induce Systemic Acquired Resistance," Plant Cell 3:49-59 (1991), which is hereby incorporated by reference). Five of these defense gene families encode pathogenesis-related proteins whose physiological functions have not been established. However, some of these proteins have antifungal activity in vitro (Bol, J. F., et al., "Plant Pathogenesis-Related Proteins Induced by Virus Infection," Ann. Rev. Phytopathol. 28:113-38 (1990), which is hereby incorporated by reference) and the constitutive expression of a bean chitinase gene in transgenic tobacco protects against infection by the fungus Rhizoctonia solani (Broglie, K., et al., "Transgenic Plants with Enhanced Resistance to the Fungal Pathogen Rhizoctonia Solani," Science 30 254:1194-1197 (1991), which is hereby incorporated by reference), suggesting that these systemic acquired resistance proteins may contribute to the immunized state (Uknes, S., et al., "Acquired Resistance in Arabidopsis," Plant Cell 4:645-656 (1992), which is hereby incorporated by reference).

Salicylic acid appears to play a signal function in the induction of systemic acquired resistance since endogenous levels increase after immunization (Malamy, J., et al., "Salicylic Acid: A Likely Endogenous Signal in the Resistance Response of Tobacco to Viral Infection," Science 250:1002-1004 (1990), which is hereby incorporated by reference) and exogenous salicylate induces systemic acquired resistance genes (Yalpani, N., et al., "Salicylic Acid is a Systemic Signal and an Inducer of Pathogenesis-Related Proteins in Virus-Infected Tobacco," Plant Cell 3:809-818 (1991), which is hereby incorporated by reference), and acquired resistance (Uknes, S., et al., "Acquired Resistance in Arabidopsis," Plant Cell 4:645-656 (1992), which is hereby incorporated by reference). Moreover, transgenic tobacco plants in which salicylate is destroyed by the action of a bacterial transgene encoding salicylate hydroxylase do not exhibit systemic acquired resistance (Gaffney, T., et al., "Requirement of Salicylic Acid for the Induction of Systemic Acquired Resistance," Science 261:754-296 (1993), which is hereby incorporated by reference). However, this effect may reflect inhibition of a local rather than a systemic signal function, and detailed kinetic analysis of signal transmission in cucumber suggests that salicylate may not be essential for long-distance signaling (Rasmussen, J. B., et al., "Systemic Induction of Salicylic Acid Accumulation in Cucumber after Inoculation with Pseudomonas Syringae pv. Syringae," Plant Physiol. 97:1342-1347) (1991), which is hereby incorporated by reference).

Immunization using biotic agents has been extensively studied. Green beans were systemically immunized against disease caused by cultivar-pathogenic races of Colletotrichum lindemuthianum by prior infection with either cultivar-nonpathogenic races (Rahe, J. E., "Induced Resistance in Phaseolus Vulgaris to Bean Anthracnose," Phytopathology 59:1641-5 (1969); Elliston, J., et al., "Induced Resistance to Anthracnose at a Distance from the Site of the Inducing Interaction," Phytopathology 61:1110-12 (1971); Skipp, R., et al., "Studies on Cross Protection in the Anthracnose Disease of Bean," Physiological Plant Pathology 3:299-313 (1973), which are hereby incorporated by reference), cultivar-pathogenic races attenuated by heat in host tissue prior to symptom appearance (Rahe, J. E., et al., "Metabolic Nature of the Infection-Limiting Effect of Heat on Bean Anthracnose," Phytopathology 60:1005-9 (1970), which is hereby incorporated by reference) or nonpathogens of bean. The anthracnose pathogen of cucumber, Colletotrichum lagenarium, was equally effective as non-pathogenic races as an inducer of systemic protection against all races of bean anthracnose. Protection was induced by C. lagenarium in cultivars resistant to one or more races of C. lindemuthianum as well as in cultivars susceptible to all reported races of the fungus and which accordingly had been referred to as `lacking genetic resistance` to the pathogen (Elliston, J., et al., "Protection of Bean Against Anthracnose by Colletotrichum Species Nonpathogenic on Bean," Phytopathologische Zeitschrift 86:117-26 (1976); Elliston, J., et al., "A Comparative Study on the Development of Compatible, Incompatible and Induced Incompatible Interactions Between Collectotrichum Species and Phaseolus Vulgaris," Phytopathologische Zeitschrift 87:289-303 (1976), which are hereby incorporated by reference). These results suggest that the same mechanisms may be induced in cultivars reported as `possessing` or `lacking` resistance genes (Elliston, J., et al., "Relation of Phytoalexin Accumulation to Local and Systemic Protection of Bean Against Anthracnose," Phytopathologische Zeitschrift 88:114-30 (1977), which is hereby incorporated by reference). It also is apparent that cultivars susceptible to all races of C. lindemuthianum do not lack genes for resistance mechanisms against the pathogen.

Kuc, J., et al., "Protection of Cucumber Against Collectotrichum Lagenarium by Colletotrichum lagenarium," Physiological Plant Pathology 7:195-9 (1975), which is hereby incorporated by reference), showed that cucumber plants could be systemically protected against disease caused by Colletotrichum lagenarium by prior inoculation of the cotyledons or the first true leaf with the same fungus. Subsequently, cucumbers have been systemically protected against fungal, bacterial, and viral diseases by prior localized infection with either fungi, bacteria, or viruses (Hammerschmidt, R., et al., "Protection of Cucumbers Against Colletotrichum Lagenarium and Cladosporium Cucumerinum," Phytopathology 66:790-3 (1976); Jenns, A. E., et al., "Localized Infection with Tobacco Necrosis Virus Protects Cucumber Against Colletotrichum Lagenarium," Physiological Plant Pathology 11:207-12 (1977); Caruso, F. L., et al. "Induced Resistance of Cucumber to Anthracnose and Angular Leaf Spot by Pseudomonas Lachrymans and Colletotrichum Lagenarium," Physiological Plant Pathology 14:191-201 (1979); Staub, T., et al., "Systemic Protection of Cucumber Plants Against Disease Caused by Cladosporium Cucumerinum and Colletotrichum Lagenarium by Prior Localized Infection with Either Fungus," Physiological Plant Pathology, 17:389-93 (1980); Bergstrom, G. C., et al., "Effects of Local Infection of Cucumber by Colletotrichum Lagenarium, Pseudomonas Lachrymans or Tobacco Necrosis Virus on Systemic Resistance to Cucumber Mosaic Virus," Phytopathology 72:922-6 (1982); Gessler, C., et al., "Induction of Resistance to Fusarium Wilt in Cucumber by Root and Foliar Pathogens," Phytopathology 72:1439-41 (1982); Basham, B., et al., "Tobacco Necrosis Virus Induces Systemic Resistance in Cucumbers Against Sphaerotheca Fuliginea," Physiological Plant Pathology 23:137-44 (1983), which are hereby incorporated by reference). Non-specific protection induced by infection with C. lagenarium or tobacco necrosis virus was effective against at least 13 pathogens, including obligatory and facultative parasitic fungi, local lesion and systemic viruses, wilt fungi, and bacteria. Similarly, protection was induced by and was also effective against root pathogens. Other curcurbits, including watermelon and muskmelon have been systemically protected against C. lagenarium (Caruso, F. L., et al., "Protection of Watermelon and Muskmelon Against Colletotrichum Lagenarium by Colletotrichum Lagenarium," Phytopathology 67:1285-9 (1977), which is hereby incorporated by reference).

Systemic protection in tobacco has also been induced against a wide variety of diseases (Kuc, J., et al., "Immunization for Disease Resistance in Tobacco," Recent Advances in Tobacco Science 9:179-213 (1983), which is hereby incorporated by reference). Necrotic lesions caused by tobacco mosaic virus enhanced resistance in the upper leaves to disease caused by the virus (Ross, A. F., et al., "Systemic Acquired Resistance Induced by Localized Virus Infections in Plants," Virology 14:340-58 (1961); Ross, A. F., et al., "Systemic Effects of Local Lesion Formation," In: Viruses of Plants pp. 127-50 (1966), which are hereby incorporated by reference). Phytophthora parasitica var. nicotianae, P. tabacina and Pseudomonas tabaci and reduced reproduction of the aphid Myzus persicae (McIntyre, J. L., et al., "Induction of Localized and Systemic Protection Against Phytophthora Parasitica var. nicotianae by Tobacco Mosaic Virus Infection of Tobacco Hypersensitive to the Virus," Physiological Plant Pathology 15:321-30 (1979); McIntyre, J. L., et al., "Effects of Localized Infections of Nicotiana Tabacum by Tobacco Mosaic Virus on Systemic Resistance Against Diverse Pathogens and an Insect," Phytopathology 71:297-301 (1981), which are hereby incorporated by reference). Infiltration of heat-killed P. tabaci (Lovrekovich, L., et al., "Induced Reaction Against Wildfire Disease in Tobacco Leaves Treated with Heat-Killed Bacteria," Nature 205:823-4 (1965), which is hereby incorporated by reference), and Pseudomonas solanacearum (Sequeira, L, et al., "Interaction of Bacteria and Host Cell Walls: Its Relation to Mechanisms of Induced Resistance," Physiological Plant Pathology 10:43-50 (1977), which are hereby incorporated by reference), into tobacco leaves induced resistance against the same bacteria used for infiltration. Tobacco plants were also protected by the nematode Pratylenchus penetrans against P. parasitica var. nicotiana (McIntyre, J. L., et al. "Protection of Tobacco Against Phytophthora Parasitica Var. Nicotianae by Cultivar-Nonpathogenic Races, Cell-Free Sonicates and Pratylenchus Penetrans," Phytopathology 68:235-9 (1978), which is hereby incorporated by reference).

Cruikshank, I. A. M., et al., "The Effect of Stem Infestation of Tobacco with Peronospora Tabacina Adam on Foliage Reaction to Blue Mould," Journal of the Australian Institute of Agricultural Science 26:369-72 (1960), which is hereby incorporated by reference, were the first to report immunization of tobacco foliage against blue mould (i.e., P. tabacina) by stem injection with the fungus, which also involved dwarfing and premature senescence. It was recently discovered that injection external to the xylem not only alleviated stunting but also promoted growth and development. Immunized tobacco plants, in both glasshouse and field experiments, were approximately 40% taller, had a 40% increase in dry weight, 30% increase in fresh weight, and 4-6 more leaves than control plants (Tuzun, S., et al., "The Effect of Stem Injections with Peronospora Tabacina and Metalaxyl Treatment on Growth of Tobacco and Protection Against Blue Mould in the Field," Phytopathology 74:804 (1984), which is hereby incorporated by reference). These plants flowered approximately 2-3 weeks earlier than control plants (Tuzun, S., et al., "Movement of a Factor in Tobacco Infected with Peronospora Tabacina Adam which Systemically Protects Against Blue Mould," Physiological Plant Pathology 26:321-30 (1985), which is hereby incorporated by reference).

Systemic protection does not confer absolute immunity against infection, but reduces the severity of the disease and delays symptom development. Lesion number, lesion size, and extent of sporulation of fungal pathogens are all decreased. The diseased area may be reduced by more than 90%.

When cucumbers were given a `booster` inoculation 3-6 weeks after the initial inoculation, immunization induced by C. lagenarium lasted through flowering and fruiting (Kuc, J., et al., "Aspects of the Protection of Cucumber Against Colletotrichum Lagenarium by Colletotrichum Lagenarium," Phytopathology 67:533-6 (1977), which is hereby incorporated by reference). Protection could not be induced once plants had set fruit. Tobacco plants were immunized for the growing season by stem injection with sporangia of P. tabacina. However, to prevent systemic blue mould development, this technique was only effective when the plants were above 20 cm in height.

Removal of the inducer leaf from immunized cucumber plants did not reduce the level of immunization of pre-existing expanded leaves. However, leaves which subsequently emerged from the apical bud were progressively less protected than their predecessors (Dean, R. A., et al., "Induced Systemic Protection in Cucumber: Time of Production and Movement of the `Signal`," Phytopathology 76:966-70 (1986), which is hereby incorporated by reference). Similar results were reported by Ross, A. F., "Systemic Effects of Local Lesion Formation," In: Viruses of Plants pp. 127-50 (1966), which is hereby incorporated by reference, with tobacco (local lesion host) immunized against tobacco mosaic virus by prior infection with tobacco mosaic virus. In contrast, new leaves which emerged from scions excised from tobacco plants immunized by stem-injection with P. tabacina were highly protected (Tuzun, S., et al., "Transfer of Induced Resistance in Tobacco to Blue Mould (Peronospora Tabacina Adam.) Via Callus," Phytopathology 75:1304 (1985), which is hereby incorporated by reference). Plants regenerated via tissue culture from leaves of immunized plants showed a significant reduction in blue mould compared to plants regenerated from leaves of non-immunized parents. Young regenerants only showed reduced sporulation. As plants aged, both lesion development and sporulation were reduced. Other investigators, however, did not reach the same conclusion, although a significant reduction in sporulation in one experiment was reported (Lucas, J. A., et al., "Nontransmissibility to Regenerants from Protected Tobacco Explants of Induced Resistance to Peronospora Hyoscyami," Phytopathology 75:1222-5 (1985), which is hereby incorporated by reference).

Protection of cucumber and watermelon is effective in the glasshouse and in the field (Caruso, F. L., et al., "Field Protection of Cucumber Against Colletotrichum Lagenarium by C. Lagenarium," Phytopathology 67:1290-2 (1977), which is hereby incorporated by reference). In one trial, the total lesion area of C. lagenarium on protected cucumber was less than 2% of the lesion areas on unprotected control plants. Similarly, only 1 of 66 protected, challenged plants died, whereas 47 of 69 unprotected, challenged watermelons died. In extensive field trials in Kentucky and Puerto Rico, stem injection of tobacco with sporangia of P. tabacina was at least as effective in controlling blue mould as the best fungicide, metalaxyl. Plants were protected 95-99%, based on the necrotic area and degree of sporulation, leading to a yield increase of 10-25% in cured tobacco.

Induced resistance against bacteria and viruses appears to be expressed as suppression of disease symptoms or pathogen multiplication or both (Caruso, F. L., et al., "Induced Resistance of Cucumber to Anthracnose and Angular Leaf Spot by Pseudomonas Lachrymans and Colletotrichum Lagenarium," Physiological Plant Pathology 14:191-201 (1979); Doss, M., et al., "Systemic Acquired Resistance of Cucumber to Pseudomonas Lachrymans as Expressed in Suppression of Symptoms, but not in Multiplication of Bacteria," Acta Phytopathologia Academiae Scientiarum Hungaricae 16: (3-4), 269-72 (1981); Jenns, A. E., et al., "Non-Specific Resistance to Pathogens Induced Systemically by Local Infection of Cucumber with Tobacco Necrosis Virus, Colletotrichum Lagenarium or Pseudomonas Lachrymans," Phytopathologia Mediterranea 18:129-34 (1979), which are hereby incorporated by reference).

As described above, research concerning systemic acquired resistance involves infecting plants with infectious pathogens. Although studies in this area are useful in understanding how systemic acquired resistance works, eliciting such resistance with infectious agents is not commercially useful, because such plant-pathogen contact can weaken or kill plants. The present invention is directed to overcoming this deficiency.

SUMMARY OF THE INVENTION

The present invention relates to a method of imparting pathogen resistance to plants. This method involves applying a hypersensitive response elicitor polypeptide or protein in a non-infectious form to a plant under conditions where the polypeptide or protein contacts cells of the plant.

Another aspect of the present invention relates to a pathogen-resistant plant with cells in contact with non-infectious hypersensitive response elicitor polypeptide or protein.

Yet another aspect of the present invention relates to a composition for imparting pathogen resistance to plants. The composition includes a non-infectious, hypersensitive response elicitor polypeptide or protein and a carrier.

The present invention has the potential to: treat plant diseases which were previously untreatable; treat diseases systemically that one would not want to treat separately due to cost; and avoid the use of infectious agents to treat diseases. The present invention can impart resistance without using agents pathogenic to the plants being treated or to plants situated nearby those treated. Since the present invention involves use of a natural product that is fully biodegradable, the environment would not be contaminated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the genetic organization of the gene cluster encoding the hypersensitive response elicitor polypeptide or protein for Erwinia amylovora (i.e. hrpN). The top line shows the restriction enzyme map of plasmid vector pCPP430, where E=Eco RI, B=Bam HI, and H=Hind III. The rectangles represent transcriptional units, and the arrows under the rectangles indicate the directions of transcription. The bigger arrow indicates the region necessary for ultimate translation of the hypersensitive response elicitor polypeptide or protein. pCPP430 hrpN⁻ is the derivative of pCPP430 in which hrpN is mutated by the insertion of transposor TnStac.

FIG. 2 is a map of plasmid vector pCPP9. Significant features are the mobilization (mob) site for conjugation; the cohesive site of λ (cos); and the partition region (par) for stable inheritance of the plasmid. B, BamHI; E, EcoRI; H, HindIII; P, PstI; S, SaII; Sm, SmaI; oriV, origin of replication; Sp^(r), spectinomycin resistance; Sm^(r), streptomycin resistance.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method of imparting pathogen resistance to plants. This method involves applying a hypersensitive response elicitor polypeptide or protein in a non-infectious form to all or part of a plant under conditions where the polypeptide or protein contacts all or part of the cells of the plant.

Another aspect of the present invention relates to a pathogen-resistant plant with cells in contact with a non-infectious hypersensitive response elicitor polypeptide or protein.

Yet another aspect of the present invention relates to a composition for imparting pathogen resistance to plants. The composition includes a non-infectious hypersensitive response elicitor polypeptide or protein and a carrier.

The hypersensitive response elicitor polypeptide or protein utilized in the present invention can correspond to hypersensitive response elicitor polypeptides or proteins derived from a wide variety of pathogens. Such polypeptides or proteins are able to elicit local necrosis in plant tissue contacted by the elicitor. Preferred pathogens include Erwinia amylovora, Erwinia chrysanthemi, Pseudomonas syringae, Pseudomonas solancearum, Xanthomonas campestris, or mixtures thereof.

For purposes of the present invention, non-infectious forms of the hypersensitive response elicitor polypeptide or protein can induce a hypersensitive response without causing disease in the plant with which the polypeptide or protein is contacted. This can be achieved in a number of ways, including: 1) application of an isolated elicitor polypetide or protein; 2) application of bacteria which do not cause disease and are transformed with genes encoding a hypersensitive response elicitor polypeptide or protein; and 3) application of bacteria which cause disease in some plant species (but not in those to which they are applied) and naturally contain a gene encoding the hypersensitive response elicitor polypeptide or protein.

In one embodiment of the present invention, the hypersensitive response elicitor polypeptides or proteins can be isolated from their corresponding organisms and applied to plants. Such isolation procedures are well known, as described in Arlat, M., F. Van Gijsegem, J. C. Huet, J. C. Pemollet, and C. A. Boucher, "PopA1, a Protein which Induces a Hypersensitive-like Response in Specific Petunia Genotypes is Secreted via the Hrp Pathway of Pseudomonas solanacearum," EMBO J. 13:543-553 (1994); He, S. Y., H. C. Huang, and A. Collmer, "Pseudomonas syringae pv. syringae Harpin_(Pss) : a Protein that is Secreted via the Hrp Pathway and Elicits the Hypersensitive Response in Plants," Cell 73:1255-1266 (1993); and Wei, Z.-M., R. J. Laby, C. H. Zumoff, D. W. Bauer, S.-Y. He, A. Collmer, and S. V. Beer, "Harpin Elicitor of the Hypersensitive Response Produced by the Plant Pathogen Erwinia amylovora, Science 257:85-88 (1992), which are hereby incorporated by reference. See also pending U.S. patent application Ser. Nos. 08/200,024 and 08/062,024, which are hereby incorporated by reference. Preferably, however, the isolated hypersensitive response elicitor polypeptides or proteins of the present invention are produced recombinantly and purified as described below.

In other embodiments of the present invention, the hypersensitive response elicitor polypeptide or protein of the present invention can be applied to plants by applying bacteria containing genes encoding the hypersensitive response elicitor polypeptide or protein. Such bacteria must be capable of secreting or exporting the polypeptide or protein so chat the elicitor can contact plant cells. In these embodiments, the hypersensitive response elicitor polypeptide or protein is produced by the bacteria in planta or just prior to introduction of the bacteria to the plants.

In one embodiment of the bacterial application mode of the present invention, the bacteria do not cause the disease and have been transformed (e.g., recombinantly) with genes encoding a hypersensitive response elicitor polypeptide or protein. For example, E. coli, which do not elicit a hypersensitive response in plants, can be transformed with genes encoding a hypersensitive response elicitor polypeptide or protein and then applied to plants. Bacterial species (other than E. coli) can also be used in this embodiment of the present invention.

In another embodiment of the bacterial application mode of the present invention, the bacteria do cause disease and naturally contain a gene encoding a hypersensitive response elicitor polypeptide or protein. Examples of such bacteria are noted above. However, in this embodiment these bacteria are applied to plants which are not susceptible to the disease carried by the bacteria. For example, Erwinia amylovora causes disease in apple or pear but not in tomato. However, such bacteria will elicit a hypersensitive response in tomato. Accordingly, in accordance with this embodiment of the present invention, Erwinia amylovora can be applied to tomato to impart pathogen resistance without causing disease in that species. The hypersensitive response elicitor polypeptide or protein from Erwinia chrysanthemi has an amino acid sequence corresponding to SEQ. ID. No. 1 as follows: ##STR1## This hypersensitive response elicitor polypeptide or protein has a molecular weight of 34 kDa, is heat stable, has a glycine content of greater than 16%, and contains substantially no cysteine. The Erwinia chrysanthemi hypersensitive response elicitor polypeptide or protein is encoded by a DNA molecule having a nucleotide sequence corresponding to SEQ. ID. No. 2 as follows:

    __________________________________________________________________________     CGATTTTACC             CGGGTGAACG                     TGCTATGACC                             GACAGCATCA                                     CGGTATTCGA                                             CACCGTTACG                                                     60     GCGTTTATGG             CCGCGATGAA                     CCGGCATCAG                             GCGGCGCGCT                                     GGTCGCCGCA                                             ATCCGGCGTC                                                     120     GATCTGGTAT             TTCAGTTTGG                     GGACACCGGG                             CGTGAACTCA                                     TGATGCAGAT                                             TCAGCCGGGG                                                     180     CAGCAATATC             CCGGCATGTT                     GCGCACGCTG                             CTCGCTCGTC                                     GTTATCAGCA                                             GGCGGCAGAG                                                     240     TGCGATGGCT             GCCATCTGTG                     CCTGAACGGC                             AGCGATGTAT                                     TGATCCTCTG                                             GTGGCCGCTG                                                     300     CCGTCGGATC             CCGGCAGTTA                     TCCGCAGGTG                             ATCGAACGTT                                     TGTTTGAACT                                             GGCGGGAATG                                                     360     ACGTTGCCGT             CGCTATCCAT                     AGCACCGACG                             GCGCGTCCGC                                     AGACAGGGAA                                             CGGACGCGCC                                                     420     CGATCATTAA             GATAAAGGCG                     GCTTTTTTTA                             TTGCAAAACG                                     GTAACGGTGA                                             GGAACCGTTT                                                     480     CACCGTCGGC             GTCACTCAGT                     AACAAGTATC                             CATCATGATG                                     CCTACATCGG                                             GATCGGCGTG                                                     540     GGCATCCGTT             GCAGATACTT                     TTGCGAACAC                             CTGACATGAA                                     TGAGGAAACG                                             AAATTATGCA                                                     600     AATTACGATC             AAAGCGCACA                     TCGGCGGTGA                             TTTGGGCGTC                                     TCCGGTCTGG                                             GGCTGGGTGC                                                     660     TCAGGGACTG             AAAGGACTGA                     ATTCCGCGGC                             TTCATCGCTG                                     GGTTCCAGCG                                             TGGATAAACT                                                     720     GAGCAGCACC             ATCGATAAGT                     TGACCTCCGC                             GCTGACTTCG                                     ATGATGTTTG                                             GCGGCGCGCT                                                     780     GGCGCAGGGG             CTGGGCGCCA                     GCTCGAAGGG                             GCTGGGGATG                                     AGCAATCAAC                                             TGGGCCAGTC                                                     840     TTTCGGCAAT             GGCGCGCAGG                     GTGCGAGCAA                             CCTGCTATCC                                     GTACCGAAAT                                             CCGGCGGCGA                                                     900     TGCGTTGTCA             AAAATGTTTG                     ATAAAGCGCT                             GGACGATCTG                                     CTGGGTCATG                                             ACACCGTGAC                                                     960     CAAGCTGACT             AACCAGAGCA                     ACCAACTGGC                             TAATTCAATG                                     CTGAACGCCA                                             GCCAGATGAC                                                     1020     CCAGGGTAAT             ATGAATGCGT                     TCGGCAGCGG                             TGTGAACAAC                                     GCACTGTCGT                                             CCATTCTCGG                                                     1080     CAACGGTCTC             GGCCAGTCGA                     TGAGTGGCTT                             CTCTCAGCCT                                     TCTCTGGGGG                                             CAGGCGGCTT                                                     1140     GCAGGGCCTG             AGCGGCGCGG                     GTGCATTCAA                             CCAGTTGGGT                                     AATGCCATCG                                             GCATGGGCGT                                                     1200     GGGGCAGAAT             GCTGCGCTGA                     GTGCGTTGAG                             TAACGTCAGC                                     ACCCACGTAG                                             ACGGTAACAA                                                     1260     CCGCCACTTT             GTAGATAAAG                     AAGATCGCGG                             CATGGCGAAA                                     GAGATCGGCC                                             AGTTTATGGA                                                     1320     TCAGTATCCG             GAAATATTCG                     GTAAACCGGA                             ATACCAGAAA                                     GATGGCTGGA                                             GTTCGCCGAA                                                     1380     GACGGACGAC             AAATCCTGGG                     CTAAAGCGCT                             GAGTAAACCG                                     GATGATGACG                                             GTATGACCGG                                                     1440     CGCCAGCATG             GACAAATTCC                     GTCAGGCGAT                             GGGTATGATC                                     AAAAGCGCGG                                             TGGCGGGTGA                                                     1500     TACCGGCAAT             ACCAACCTGA                     ACCTGCGTGG                             CGCGGGCGGT                                     GCATCGCTGG                                             GTATCGATGC                                                     1560     GGCTGTCGTC             GGCGATAAAA                     TAGCCAACAT                             GTCGCTGGGT                                     AAGCTGGCCA                                             ACGCCTGATA                                                     1620     ATCTGTGCTG             GCCTGATAAA                     GCGGAAACGA                             AAAAAGAGAC                                     GGGGAAGCCT                                             GTCTCTTTTC                                                     1680     TTATTATGCG             GTTTATGCGG                     TTACCTGGAC                             CGGTTAATCA                                     TCGTCATCGA                                             TCTGGTACAA                                                     1740     ACGCACATTT             TCCCGTTCAT                     TCGCGTCGTT                             ACGCGCCACA                                     ATCGCGATGG                                             CATCTTCCTC                                                     1800     GTCGCTCAGA             TTGCGCGGCT                     GATGGGGAAC                             GCCGGGTGGA                                     ATATAGAGAA                                             ACTCGCCGGC                                                     1860     CAGATGGAGA             CACGTCTGCG                     ATAAATCTGT                             GCCGTAACGT                                     GTTTCTATCC                                             GCCCCTTTAG                                                     1920     CAGATAGATT             GCGGTTTCGT                     AATCAACATG                             GTAATGCGGT                                     TCCGCCTGTG                                             CGCCGGCCGG                                                     1980     GATCACCACA             ATATTCATAG                     AAAGCTGTCT                             TGCACCTACC                                     GTATCGCGGG                                             AGATACCGAC                                                     2040     AAAATAGGGC             AGTTTTTGCG                     TGGTATCCGT                             GGGGTGTTCC                                     GGCCTGACAA                                             TCTTGAGTTG                                                     2100     GTTCGTCATC             ATCTTTCTCC                     ATCTGGGCGA                             CCTGATCGGT                                     T               2141     __________________________________________________________________________

The hypersensitive response elicitor polypeptide or protein derived from Erwinia amylovora has an amino acid sequence corresponding to SEQ. ID. No. 3 as follows: ##STR2## This hypersensitive response elicitor polypeptide or protein has a molecular weight of about 37 kDa, it has a pI of approximately 4.3, and is heat stable at 100° C. for at least 10 minutes. This hypersensitive response elicitor polypeptide or protein has substantially no cysteine. The hypersensitive response elicitor polypeptide or protein derived from Erwinia amylovora is more fully described in Wei, Z.-M., R. J. Laby, C. H. Zumoff, D. W. Bauer, S.-Y. He, A. Collmer, and S. V. Beer, "Harpin, Elicitor of the Hypersensitive Response Produced by the Plant Pathogen Erwinia amylovora," Science 257:85-88 (1992), which is hereby incorporated by reference. The DNA molecule encoding this polypeptide or protein has a nucleotide sequence corresponding to SEQ. ID. No. 4 as follows:

    __________________________________________________________________________     ATGAGTCTGA             ATACAAGTGG                     GCTGGGAGCG                             TCAACGATGC                                     AAATTTCTAT                                             CGGCGGTGCG                                                     60     GGCGGAAATA             ACGGGTTGCT                     GGGTACCAGT                             CGCCAGAATG                                     CTGGGTTGGG                                             TGGCAATTCT                                                     120     GCACTGGGGC             TGGGCGGCGG                     TAATCAAAAT                             GATACCGTCA                                     ATCAGCTGGC                                             TGGCTTACTC                                                     180     ACCGGCATGA             TGATGATGAT                     GAGCATGATG                             GGCGGTGGTG                                     GGCTGATGGG                                             CGGTGGCTTA                                                     240     GGCGGTGGCT             TAGGTAATGG                     CTTGGGTGGC                             TCAGGTGGCC                                     TGGGCGAAGG                                             ACTGTCGAAC                                                     300     GCGCTGAACG             ATATGTTAGG                     CGGTTCGCTG                             AACACGCTGG                                     GCTCGAAAGG                                             CGGCAACAAT                                                     360     ACCACTTCAA             CAACAAATTC                     CCCGCTGGAC                             CAGGCGCTGG                                     GTATTAACTC                                             AACGTCCCAA                                                     420     AACGACGATT             CCACCTCCGG                     CACAGATTCC                             ACCTCAGACT                                     CCAGCGACCC                                             GATGCAGCAG                                                     480     CTGCTGAAGA             TGTTCAGCGA                     GATAATGCAA                             AGCCTGTTTG                                     GTGATGGGCA                                             AGATGGCACC                                                     540     CAGGGCAGTT             CCTCTGGGGG                     CAAGCAGCCG                             ACCGAAGGCG                                     AGCAGAACGC                                             CTATAAAAAA                                                     600     GGAGTCACTG             ATGCGCTGTC                     GGGCCTGATG                             GGTAATGGTC                                     TGAGCCAGCT                                             CCTTGGCAAC                                                     660     GGGGGACTGG             GAGGTGGTCA                     GGGCGGTAAT                             GCTGGCACGG                                     GTCTTGACGG                                             TTCGTCGCTG                                                     720     GGCGGCAAAG             GGCTGCAAAA                     CCTGAGCGGG                             CCGGTGGACT                                     ACCAGCAGTT                                             AGGTAACGCC                                                     780     GTGGGTACCG             GTATCGGTAT                     GAAAGCGGGC                             ATTCAGGCGC                                     TGAATGATAT                                             CGGTACGCAC                                                     840     AGGCACAGTT             CAACCCGTTC                     TTTCGTCAAT                             AAAGGCGATC                                     GGGCGATGGC                                             GAAGGAAATC                                                     900     GGTCAGTTCA             TGGACCAGTA                     TCCTGAGGTG                             TTTGGCAAGC                                     CGCAGTACCA                                             GAAAGGCCCG                                                     960     GGTCAGGAGG             TGAAAACCGA                     TGACAAATCA                             TGGGCAAAAG                                     CACTGAGCAA                                             GCCAGATGAC                                                     1020     GACGGAATGA             CACCAGCCAG                     TATGGAGCAG                             TTCAACAAAG                                     CCAAGGGCAT                                             GATCAAAAGG                                                     1080     CCCATGGCGG             GTGATACCGG                     CAACGGCAAC                             CTGCAGCACG                                     CGGTGCCGGT                                             GGTTCTTCGC                                                     1140     TGGGTATTGA             TGCCATGA                                1158     __________________________________________________________________________

The hypersensitive response elicitor polypeptide or protein derived from Pseudomonas syringae has an amino acid sequence corresponding to SEQ. ID. No. 5 as follows: ##STR3## This hypersensitive response elicitor polypeptide or protein has a molecular weight of 34-35 kDa. It is rich in glycine (about 13.5%) and lacks cysteine and tyrosine. Further information about the hypersensitive response elicitor derived from Pseudomonas syringae is found in He, S. Y., H. C. Huang, and A. Collmer, "Pseudomonas syringae pv. syringae Harpin_(Pss) : a Protein that is Secreted via the Hrp Pathway and Elicits the Hypersensitive Response in Plants," Cell 73:1255-1266 (1993), which is hereby incorporated by reference. The DNA molecule encoding the hypersensitive response elicitor from Pseudomonas syringae has a nucleotide sequence corresponding to SEQ. ID. No. 6 as follows:

    __________________________________________________________________________     ATGCAGAGTC             TCAGTCTTAA                     CAGCAGCTCG                             CTGCAAACCC                                     CGGCAATGGC                                             CCTTGTCCTG                                                     60     GTACGTCCTG             AAGCCGAGAC                     GACTGGCAGT                             ACGTCGAGCA                                     AGGCGCTTCA                                             GGAAGTTGTC                                                     120     GTGAAGCTGG             CCGAGGAACT                     GATGCGCAAT                             GGTCAACTCG                                     ACGACAGCTC                                             GCCATTGGGA                                                     180     AAACTGTTGG             CCAAGTCGAT                     GGCCGCAGAT                             GGCAAGGCGG                                     GCGGCGGTAT                                             TGAGGATGTC                                                     240     ATCGCTGCGC             TGGACAAGCT                     GATCCATGAA                             AAGCTCGGTG                                     ACAACTTCGG                                             CGCGTCTGCG                                                     300     GACAGCGCCT             CGGGTACCGG                     ACAGCAGGAC                             CTGATGACTC                                     AGGTGCTCAA                                             TGGCCTGGCC                                                     360     AAGTCGATGC             TCGATGATCT                     TCTGACCAAG                             CAGGATGGCG                                     GGACAAGCTT                                             CTCCGAAGAC                                                     420     GATATGCCGA             TGCTGAACAA                     GATCGCGCAG                             TTCATGGATG                                     ACAATCCCGC                                             ACAGTTTCCC                                                     480     AAGCCGGACT             CGGGCTCCTG                     GGTGAACGAA                             CTCAAGGAAG                                     ACAACTTCCT                                             TGATGGCGAC                                                     540     GAAACGGCTG             CGTTCCGTTC                     GGCACTCGAC                             ATCATTGGCC                                     AGCAACTGGG                                             TAATCAGCAG                                                     600     AGTGACGCTG             GCAGTCTGGC                     AGGGACGGGT                             GGAGGTCTGG                                     GCACTCCGAG                                             CAGTTTTTCC                                                     660     AACAACTCGT             CCGTGATGGG                     TGATCCGCTG                             ATCGACGCCA                                     ATACCGGTCC                                             CGGTGACAGC                                                     720     GGCAATACCC             GTGGTGAAGC                     GGGGCAACTG                             ATCGGCGAGC                                     TTATCGACCG                                             TGGCCTGCAA                                                     780     TCGGTATTGG             CCGGTGGTGG                     ACTGGGCACA                             CCCGTAAACA                                     CCCCGCAGAC                                             CGGTACGTCG                                                     840     GCGAATGGCG             GACAGTCCGC                     TCAGGATCTT                             GATCAGTTGC                                     TGGGCGGCTT                                             GCTGCTCAAG                                                     900     GGCCTGGAGG             CAACGCTCAA                     GGATGCCGGG                             CAAACAGGCA                                     CCGACGTGCA                                             GTCGAGCGCT                                                     960     GCGCAAATCG             CCACCTTGCT                     GGTCAGTACG                             CTGCTGCAAG                                     GCACCCGCAA                                             TCAGGCTGCA                                                     1020     GCCTGA                                          1026     __________________________________________________________________________

The hypersensitive response elicitor polypeptide or protein derived from Pseudomonas solanacearum has an amino acid sequence corresponding to SEQ. ID. No. 7 as follows: ##STR4## It is encoded by a DNA molecule having a nucleotide sequence corresponding SEQ. ID. No. 8 as follows:

    __________________________________________________________________________     ATGTCAGTCG             GAAACATCCA                     GAGCCCGTCG                             AACCTCCCGG                                     GTCTGCAGAA                                             CCTGAACCTC                                                     60     AACACCAACA             CCAACAGCCA                     GCAATCGGGC                             CAGTCCGTGC                                     AAGACCTGAT                                             CAAGCAGGTC                                                     120     GAGAAGGACA             TCCTCAACAT                     CATCGCAGCC                             CTCGTGCAGA                                     AGGCCGCACA                                             GTCGGCGGGC                                                     180     GGCAACACCG             GTAACACCGG                     CAACGCGCCG                             GCGAAGGACG                                     GCAATGCCAA                                             CGCGGGCGCC                                                     240     AACGACCCGA             GCAAGAACGA                     CCCGAGCAAG                             AGCCAGGCTC                                     CGCAGTCGGC                                             CAACAAGACC                                                     300     GGCAACGTCG             ACGACGCCAA                     CAACCAGGAT                             CCGATGCAAG                                     CGCTGATGCA                                             GCTGCTGGAA                                                     360     GACCTGGTGA             AGCTGCTGAA                     GGCGGCCCTG                             CACATGCAGC                                     AGCCCGGCGG                                             CAATGACAAG                                                     420     GGCAACGGCG             TGGGCGGTGC                     CAACGGCGCC                             AAGGGTGCCG                                     GCGGCCAGGG                                             CGGCCTGGCC                                                     480     GAAGCGCTGC             AGGAGATCGA                     GCAGATCCTC                             GCCCAGCTCG                                     GCGGCGGCGG                                             TGCTGGCGCC                                                     540     GGCGGCGCGG             GTGGCGGTGT                     CGGCGGTGCT                             GGTGGCGCGG                                     ATGGCGGCTC                                             CGGTGCGGGT                                                     600     GGCGCAGGCG             GTGCGAACGG                     CGCCGACGGC                             GGCAATGGCG                                     TGAACGGCAA                                             CCAGGCGAAC                                                     660     GGCCCGCAGA             ACGCAGGCGA                     TGTCAACGGT                             GCCAACGGCG                                     CGGATGACGG                                             CAGCGAAGAC                                                     720     CAGGGCGGCC             TCACCGGCGT                     GCTGCAAAAG                             CTGATGAAGA                                     TCCTGAACGC                                             GCTGGTGCAG                                                     780     ATGATGCAGC             AAGGCGGCCT                     CGGCGGCGGC                             AACCAGGCGC                                     AGGGCGGCTC                                             GAAGGGTGCC                                                     840     GGCAACGCCT             CGCCGGCTTC                     CGGCGCGAAC                             CCGGGCGCGA                                     ACCAGCCCGG                                             TTCGGCGGAT                                                     900     GATCAATCGT             CCGGCCAGAA                     CAATCTGCAA                             TCCCAGATCA                                     TGGATGTGGT                                             GAAGGAGGTC                                                     960     GTCCAGATCC             TGCAGCAGAT                     GCTGGCGGCG                             CAGAACGGCG                                     GCAGCCAGCA                                             GTCCACCTCG                                                     1020     ACGCAGCCGA             TGTAA                                   1035     __________________________________________________________________________

Further information regarding the hypersensitive response elicitor polypeptide or protein derived from Pseudomonas solanacearum is set forth in Arlat, M., F. Van Gijsegem, J. C. Huet, J. C. Pemollet, and C. A. Boucher, "PopA1, a Protein which Induces a Hypersensitive-like Response in Specific Petunia Genotypes, is Secreted via the Hrp Pathway of Pseudomonas solanacearum," EMBO J. 13:543-533 (1994), which is hereby incorporated by reference.

The hypersensitive response elicitor polypeptide or protein from Xanthomonas campestris pv. glycines has an amino acid sequence corresponding to SEQ. ID. No. 9 as follows: ##STR5## This sequence is an amino terminal sequence having 26 residues only from the hypersensitive response elicitor polypeptide or protein of Xanthomonas campestris pv. glycines. It matches with fimbrial subunit proteins determined in other tanthomouas campestris pathovars.

The above elicitors are exemplary. Other elicitors can be identified by growing bacteria that elicit a hypersensitive response under which genes encoding an elicitor are expressed. Cell-free preparations from culture supernatants can be tested for elicitor activity (i.e. local necrosis) by using them to infiltrate appropriate plant tissues.

It is also possible to use fragments of the above hypersensitive response elicitor polypeptides or proteins as well as fragments of full length elicitors from other pathogens, in the method of the present invention.

Suitable fragments can be produced by several means. In the first, subclones of the gene encoding a known elicitor protein are produced by conventional molecular genetic manipulation by subcloning gene fragments. The subclones then are expressed in vitro or in vivo in bacterial cells to yield a smaller protein or a peptide that can be tested for elicitor activity according to the procedure described below.

As an alternative, fragments of an elicitor protein can be produced by digestion of a full-length elicitor protein with proteolytic enzymes like chymotrypsin or Staphylococcus proteinase A, or trypsin. Different proteolytic enzymes are likely to cleave elicitor proteins at different sites based on the amino acid sequence of the elicitor protein. Some of the fragments that result from proteolysis may be active elicitors of resistance.

In another approach, based on knowledge of the primary structure of the protein, fragments of the elicitor protein gene may be synthesized by using the PCR technique together with specific sets of primers chosen to represent particular portions of the protein. These then would be cloned into an appropriate vector for increase and expression of a truncated peptide or protein.

Variants may also (or alternatively) be modified by, for example, the deletion or addition of amino acids that have minimal influence on the properties, secondary structure and hydropathic nature of the polypeptide. For example, a polypeptide may be conjugated to a signal (or leader) sequence at the N-terminal end of the protein which co-translationally or post-translationally directs transfer of the protein. The polypeptide may also be conjugated to a linker or other sequence for ease of synthesis, purification or identification of the polypeptide.

The protein or polypeptide of the present invention is preferably produced in purified form (preferably at least about 80%, more preferably 90%, pure) by conventional techniques. Typically, the protein or polypeptide of the present invention is secreted into the growth medium of recombinant E. coli. To isolate the protein, the E. coli host cell carrying a recombinant plasmid is propagated, homogenized, and the homogenate is centrifuged to remove bacterial debris. The supernatant is then subjected to sequential ammonium sulfate precipitation. The fraction containing the polypeptide or protein of the present invention is subjected to gel filtration in an appropriately sized dextran or polyacrylamide column to separate the proteins. If necessary, the protein fraction may be further purified by HPLC.

The DNA molecule encoding the hypersensitive response elicitor polypeptide or protein can be incorporated in cells using conventional recombinant DNA technology. Generally, this involves inserting the DNA molecule into an expression system to which the DNA molecule is heterologous (i.e. not normally present). The heterologous DNA molecule is inserted into the expression system or vector in proper sense orientation and correct reading frame. The vector contains the necessary elements for the transcription and translation of the inserted protein-coding sequences.

U.S. Pat. No. 4,237,224 to Cohen and Boyer, which is hereby incorporated by reference, describes the production of expression systems in the form of recombinant plasmids using restriction enzyme cleavage and ligation with DNA ligase. These recombinant plasmids are then introduced by means of transformation and replicated in unicellular cultures including procaryotic organisms and eucaryotic cells grown in tissue culture.

Recombinant genes may also be introduced into viruses, such as vaccina virus. Recombinant viruses can be generated by transection of plasmids into cells infected with virus.

Suitable vectors include, but are not limited to, the following viral vectors such as lambda vector system gt11, gt WES.tB, Charon 4, and plasmid vectors such as pBR322, pBR325, pACYC177, pACYC184, pUC8, pUC9, pUC18, pUC19, pLG339, pR290, pKC37, pKC101, SV 40, pBluescript II SK +/- or KS +/- (see "Stratagene Cloning Systems" Catalog (1993) from Stratagene, La Jolla, Calif., which is hereby incorporated by reference), pQE, pIH821, pGEX, pET series (see F. W. Studier et. al., "Use of T7 RNA Polymerase to Direct Expression of Cloned Genes," Gene Expression Technology vol. 185 (1990), which is hereby incorporated by reference), and any derivatives thereof. Recombinant molecules can be introduced into cells via transformation, particularly transduction, conjugation, mobilization, or electroporation. The DNA sequences are cloned into the vector using standard cloning procedures in the art, as described by Maniatis et al., Molecular Cloning: A Laboratory Manual, Cold Springs Laboratory, Cold Springs Harbor, N.Y. (1982), which is hereby incorporated by reference.

A variety of host-vector systems may be utilized to express the protein-encoding sequence(s). Primarily, the vector system must be compatible with the host cell used. Host-vector systems include but are not limited to the following: bacteria transformed with bacteriophage DNA, plasmid DNA, or cosmid DNA; microorganisms such as yeast containing yeast vectors; mammalian cell systems infected with virus (e.g., vaccinia virus, adenovirus, etc.); insect cell systems infected with virus (e.g., baculovirus); and plant cells infected by bacteria. The expression elements of these vectors vary in their strength and specificities. Depending upon the host-vector system utilized, any one of a number of suitable transcription and translation elements can be used.

Different genetic signals and processing events control many levels of gene expression (e.g., DNA transcription and messenger RNA (mRNA) translation).

Transcription of DNA is dependent upon the presence of a promotor which is a DNA sequence that directs the binding of RNA polymerase and thereby promotes mRNA synthesis. The DNA sequences of eucaryotic promoters differ from those of procaryotic promoters. Furthermore, eucaryotic promoters and accompanying genetic signals may not be recognized in or may not function in a procaryotic system, and, further, procaryotic promoters are not recognized and do not function in eucaryotic cells.

Similarly, translation of mRNA in procaryotes depends upon the presence of the proper procaryotic signals which differ from those of eucaryotes. Efficient translation of MRNA in procaryotes requires a ribosome binding site called the Shine-Dalgarno ("SD") sequence on the mRNA. This sequence is a short nucleotide sequence of mRNA that is located before the start codon, usually AUG, which encodes the amino-terminal methionine of the protein. The SD sequences are complementary to the 3'-end of the 16S rRNA (ribosomal RNA) and probably promote binding of mRNA to ribosomes by duplexing with the rRNA to allow correct positioning of the ribosome. For a review on maximizing gene expression, see Roberts and Lauer, Methods in Enzymology, 68:473 (1979), which is hereby incorporated by reference.

Promotors vary in their "strength" (i.e. their ability to promote transcription) For the purposes of expressing a cloned gene, it is desirable to use strong promoters in order to obtain a high level of transcription and, hence, expression of the gene. Depending upon the host cell system utilized, any one of a number of suitable promotors may be used. For instance, when cloning in E. coli, its bacteriophages, or plasmids, promoters such as the T7 phage promoter, lac promotor, trp promotor, recA promotor, ribosomal RNA promotor, the P_(R) and P_(L) promoters of coliphage lambda and others, including but not limited, to lacUV5, ompF, bla, lpp, and the like, may be used to direct high levels of transcription of adjacent DNA segments. Additionally, a hybrid trp-lacUV5 (tac) promotor or other E. coli promoters produced by recombinant DNA or other synthetic DNA techniques may be used to provide for transcription of the inserted gene.

Bacterial host cell strains and expression vectors may be chosen which inhibit the action of the promotor unless specifically induced. In certain operations, the addition of specific inducers is necessary for efficient transcription of the inserted DNA. For example, the lac operon is induced by the addition of lactose or IPTG (isopropylthio-beta-D-galactoside). A variety of other operons, such as trp, pro, etc., are under different controls.

Specific initiation signals are also required for efficient gene transcription and translation in procaryotic cells. These transcription and translation initiation signals may vary in "strength" as measured by the quantity of gene specific messenger RNA and protein synthesized, respectively. The DNA expression vector, which contains a promoter, may also contain any combination of various "strong" transcription and/or translation initiation signals. For instance, efficient translation in E. coli requires a Shine-Dalgarno (SD) sequence about 7-9 bases 5' to the initiation codon (ATG) to provide a ribosome binding site. Thus, any SD-ATG combination that can be utilized by host cell ribosomes may be employed. Such combinations include but are not limited to the SD-ATG combination from the cro gene or the N gene of coliphage lambda, or from the E. coli tryptophan E, D, C, B or A genes. Additionally, any SD-ATG combination produced by recombinant DNA or other techniques involving incorporation of synthetic nucleotides may be used.

Once the isolated DNA molecule encoding the hypersensitive response elicitor polypeptide or protein has been cloned into an expression system, it is ready to be incorporated into a host cell. Such incorporation can be carried out by the various forms of transformation noted above, depending upon the vector/host cell system. Suitable host cells include, but are not limited to, bacteria, virus, yeast, mammalian cells, insect, plant, and the like.

The method of the present invention can be utilized to treat a wide variety of plants to impart pathogen resistance. Suitable plants include dicots and monocots. More particularly, useful crop plants can include: rice, wheat, barley, rye, cotton, sunflower, peanut, corn, potato, sweet potato, bean, pea, chicory, lettuce, endive, cabbage, cauliflower, broccoli, turnip, radish, spinach, onion, garlic, eggplant, pepper, celery, carrot, squash, pumpkin, zucchini, cucumber, apple, pear, melon, strawberry, grape, raspberry, pineapple, soybean, tobacco, tomato, sorghum, and sugarcane. Examples of suitable ornamental plants are: Arabidopsis thaliana, Saintpaulia, petunia, pelargonium poinsettia, chrysanthemum, carnation, and zinnia.

The method of imparting pathogen resistance to plants in accordance with the present invention is useful in imparting resistance to a wide variety of pathogens including viruses, bacteria, and fungi.

Resistance, inter alia, to the following viruses can be achieved by the method of the present invention: Tobacco mosaic virus and tomato mosaic virus.

Resistance, inter alia, to the following bacteria can also be imparted to plants in accordance with the present invention: Pseudomonas solancearum, Pseudomonas syringae pv. tabaci, and Xanthamonas campestris pv. pelargonii.

Plants can be made resistant, inter alia, to the following fungi by use of the method of the present invention: Fusarium oxysporum and Phytophthora infestans.

The method of the present invention can be carried out through a variety of procedures for applying the hypersensitive response elicitor polypeptide or protein to all or part of the plant being treated. This may (but need not) involve infiltration of the hypersensitive response elicitor polypeptide or protein into the plant. Suitable application methods include high or low pressure spraying, injection, and leaf abrasion proximate to when elicitor application takes place. Other suitable application procedures can be envisioned by those skilled in the art provided they are able to effect contact of the hypersensitive response elicitor polypeptide or protein with cells of the plant.

The hypersensitive response elicitor polypeptide or protein can be applied to plants in accordance with the present invention alone or in a mixture with other materials.

One aspect of the present invention involves a composition for imparting pathogen resistance to plants containing a hypersensitive response elicitor polypeptide or protein in a carrier. Suitable carriers include water or aqueous solutions. In this embodiment, the composition contains greater than 500 nM hypersensitive response elicitor polypeptide or protein.

Although not required, this composition may contain additional additives including fertilizer, insecticide, fungicide, and mixtures thereof. Suitable fertilizers include (NH₄)₂ NO₃. An example of a suitable insecticide is Malathion. Useful fungicides include Captan.

Other suitable additives include buffering agents, wetting agents, and abrading agents. These materials can be used to facilitate the process of the present invention.

EXAMPLES Example 1

Harpin-induced Resistance of Tomato Against the Southern Bacterial Wilt Disease (Pseudomonas solanacearum)

Two-week-old tomato seedlings, grown in 8×15 cm flats in the greenhouse were treated as follows: 20 plants were used for each of the six treatments, which were designated A through F, and are described as follows:

(A) About 100 μl of a 200 μg/ml crude harpin (i.e. hypersensitive response elicitor polypeptide or protein) preparation (Z-M. Wei, "Harpin, Elicitor of the Hypersensitive Response Produced by the Plant Pathogen Erwinia amylovora," Science 257:85-88 (1992), which is hereby incorporated by reference) was infiltrated into the lowest true leaf of each of the seedlings.

(B) The same harpin preparation as used in (A) was sprayed with 400-mesh carborundum onto the leaf surface of the seedlings and then gently rubbed in with the thumb.

(C) E. coli DH5(pCPP430) (See FIG. 1 for map of plasmid vector pCPP430) was grown in LB medium to OD₆₂₀ =0.7. The culture was centrifuged and then resuspended in 5 mM of potassium phosphate buffer pH 6.5. About 100 μl of cell suspension was infiltrated into each leaf of the seedlings.

(D) E. coli DH5(pCPP430::hrpN⁻) (See FIG. 1 for map of plasmid vector pCPP430::hrpN⁻) was used as in (C). The cells were grown, and the suspension and the amount of inoculum used were the same as described in (C).

(E) For E. coli DH5(pCPP9) (See FIG. 2), the cells were grown and the suspension and the amount of inoculum used were the same as described in (C).

(F) Infiltration of leaves with 5 mM potassium phosphate buffer was as described in (C).

The challenge pathogenic bacterium, Pseudomonas solanacearum strain K60, was grown in King's medium B to OD₆₂₀ =0.7 (about 10⁸ cfu/ml). The culture was centrifuged and resuspended in 100 volume of 5 mM potassium phosphate buffer to a final concentration of about 1×10⁶ cfu/ml.

Three days after the tomato seedlings were treated with harpin or bacteria, they were pulled up and about one cm of roots were cut off with scissors. The seedlings were then dipped into the suspension of P. solanacearum K60 for 3 min. The inoculated plants were replanted into the same pots. The plants were left in a greenhouse, and the disease incidence was recorded 7 days after inoculation.

A. Effect of treatment with harpin

After 24 hours, only those leaf portions that had been infiltrated with harpin or E. coli DH5(pCPP430) had collapsed. Leaves sprayed with harpin and carborundum showed only spotty necrosis.

B. Effect of treatment with harpin on the development of Southern Bacterial Wilt.

None of the 20 harpin-infiltrated plants showed any symptoms one week after inoculation with P. solanacearum K60 (Table 1). One out of the 20 plants showed stunting symptoms. However, 7 of the 20 buffer-infiltrated plants showed stunting symptoms. Treatment with E. coli DH5(pCPP430⁻) (a transposon-induced mutant unable to elicit the hypersensitive collapse) or E. coli DH5(pCPP9) did not show significant difference compared to the plants treated with buffer. These results suggest that harpin or E. coli DH5(pCPP430), which produces harpin, induced resistance in the tomato plants to southern bacterial wilt caused by P. solanacearum K60.

                  TABLE 1     ______________________________________     Disease incidence of tomato seedlings 7 and 14     days after inoculation with P. solanacearum     K60.                 Number of Plants                 Day 7     Day 14     Treatment     Stunted Healthy Stunted Healthy     ______________________________________     A. Harpin infiltration                   0       20      2       18     B. Harpin spray                   1       19      3       17     C. E. coli DH5 (pCPP430)                   2       18      3       17     D. E. coli DH5 (pCPP430.sup.-)                   4       16      7       13     E. E. coli DH5 (pCPP9)                   5       15      6 + 1 wilted                                           13     F. Buffer     7       13      8 + 1 wilted                                           11     No pathogen   0       20      0       20     ______________________________________

Four weeks after inoculation, plants treated with the harpin or E. coli DH5(pcPP430) were taller and broader as compared to those treated with buffer. The average hieghts of 10 plants that had been infiltrated with harpin or buffer are given in Table 2.

                  TABLE 2     ______________________________________     Heights (cm) of tomato plants four weeks after     inoculation with Pseudomonas solanacearum K60,     following treatment with harpin or buffer.     Infiltrated with Buffer                 Infiltrated with Harpin                               Infiltrated with Buffer     Not inoculated                 Inoculated with K60                               Inoculated with K60     ______________________________________     36          32            11     41          29            21     35          38            33     34          35            12     39          37            15     35          33            32     36          22            25     35          35            15     41          40            37     37          29            38     Average 36.9                 33            23.9     ______________________________________

Example 2

Harpin-induced Resistance of Tomato against Southern Bacterial Wilt Disease Pseudomonas solanacearuim

All the methods used for infiltration and inoculation were the same as described in Example 1, except that the concentration of P. solanacearum K60 was about 5×10⁴ cfu/ml.

The buffer-infiltrated plants showed symptoms 15 days after inoculation with P. solanacearum K60. Six out of 20 plants showed stunting symptoms after 15 days; 2 plants were wilted after 21 days. The wilted plants eventually died. However, none of the 20 harpin-treated plants showed stunting symptoms. Three weeks after inoculation, 3 of the 20 harpin-treated plants showed stunting symptoms. It is possible that after three weeks, the plants may have lost their induced resistance. As in the first experiment, the overall girth and heights of the harpin-treated plants were greater than those treated with buffer.

Example 3

Harpin-induced Resistance of Tomato against Southern Bacterial Wilt Disease Pseudomonas solanacearum

This experiment was similar to Example 1, except that additional inoculum of Pseudomonas solanacearum K60 was added to the pots containing the treated tomato plants.

Harpin was infiltrated into two-week-old tomato seedlings. Two panels of each plant were infiltrated with about 200 μl harpin suspended in 5 mM of potassium phosphate buffer at the concentration about 200 μg/ml. A total of 20 tomato seedlings were infiltrated. The same number of tomato seedlings were infiltrated with buffer. After two days, the plants were inoculated with Pseudomonas solanacearum K60 by root-dipping. The harpin- or buffer-infiltrated plants were pulled from the soil mix and small amounts of roots were cut off with scissors and then the remaining roots were dipped into a suspension of P. solanacearum K60 for three minutes. The concentration of the bacterial cell suspension was about 5×10⁸ cfu/ml. The seedlings were replanted into the same pot. An additional 3 ml of bacterial suspension was added to the soil of each individual 4-inch diameter pot. Disease incidence was scored after one week. All the experiments were done in the greenhouse with limited temperature control.

After three weeks, 11 of the 20 buffer-infiltrated tomato plants had died and 2 plants that had wilted recovered, but remained severely stunted. Only 4 plants grew normally compared with non-inoculated tomatoes. However, 15 of the harpited plants appeared healthy; three plants were stunted and two plants were wilted 3 weeks after inoculation. These results are summarized below in Table 3.

                  TABLE 3     ______________________________________     Harpin-induced resistance of tomato against     bacterial wilt disease caused by P.     solanacearum              Weeks After Inoculation     Treatment  1             2     3     ______________________________________     Harpin     Healthy    20            17    15     Wilted     0             1     2     Stunted    0             2     3     Buffer     Healthy    8             5     4     Wilted     8             12    13     Stunted    4             3     3     ______________________________________

Example 4

Harpin-induced Resistance of Tobacco to Tobacco Mosaic Virus

One panel of a lower leaf of four-week old tobacco seedlings (cultivar, Xanthi, with N gene) were infiltrated with E. amylovora harpin at the concentration of 200 μg/ml. After three days, the plants were challenged with tobacco mosaic virus ("TMV"). Two concentrations of the virus (5 μg and 100 μg/ml) were used. About 50 μl of the virus suspension was deposited on one upper tobacco leaf. The leaf was dusted with 400-mesh carborundum and the leaves gently rubbed. Each concentration was tested on three plants. Necrotic lesions were counted 4 days after inoculation and on two subsequent days and the mean number on three leaves is reported (Table 4). It was difficult to distinguish the individual lesions by Day 10 because some of the necrotic lesions had merged together. Therefore, the number of lesions recorded seemed less than those recorded on Day 7. The size of the necrotic lesions in buffer-treated leaves was much larger than the harpin-treated leaves

                  TABLE 4     ______________________________________     Harpin-induced resistance of tobacco against     TMV from inoculation with 5 μg/ml of virus             Mean Number of Lesions/Leaf     Treatment Day 4        Day 7   Day 10     ______________________________________     Harpin    21           32      35     Buffer    67           102     76     ______________________________________

There was no significant difference in the number of local lesions that developed on the harpin-treated and buffer-treated tobacco when the tobacco mosaic virus inoculum concentration was 100 μg/ml.

Example 5

Harpin-induced Resistance of Tomato to Fusarium Wilt Disease

Six-week-old tomato plants were treated with harpin as described for Example 3. The fungal pathogen, Fusarium oxysporum, was grown on Lima Bean Agar medium for 5 days at 27° C. Two entire agar plates with mycelia were blended for 2 minutes in 20 ml of 5 mM potassium phosphate buffer. The roots of harpin- or buffer-treated tomato plants were wounded by plunging a wooden stake into the soil of the pots. Then, 3 ml of the fungal suspension was poured into the soil of each 4-inch pot. The inoculated plants remained in a controlled environment chamber at 24° C. with 16 hours of light per day. Disease incidence was recorded 7 days after inoculation. Each treatment was applied to 10 plants. The results are shown below in Table 5.

                  TABLE 5     ______________________________________     Effect of harpin or buffer treatment on     Fusarium wilt disease of tomato     Number of plants (of 10) showing wilt symptoms     at the indicated time post-inoculation     Treatment Day 7   Day 10     Day 15                                        Day 20     ______________________________________     Harpin    1       2          4     4 (1 dead)     Buffer    3       6          7     7 (4 dead)     ______________________________________

Example 6

Harpin-Induced Resistance of Tobacco Against Wildfire Disease (Pseudomonas syringae pv. tabaci).

Harpin was infiltrated into single panels of the lower leaves of 4-week-old tobacco plants (20 cm high). After three days, suspensions of Pseudomonas syringe pv. tabaci were infiltrated into single panels of upper leaves. Four days later, disease incidence was recorded, as set forth in Table 6.

                  TABLE 6     ______________________________________     Symptoms of infection by Wildfire disease in     tobacco leaves inoculated with Pseudomonas     syringe pv. tabaci following treatment of lower     leaves with harpin.     Concentration of     p.s. tabaci                Treated with Harpin                              Not treated with Harpin     ______________________________________     10.sup.4 cfu/ml                no symptoms   necrosis and water-soaking     10.sup.5 cfu/ml                no symptoms   necrosis and water-soaking     10.sup.6 cfu/ml                no symptoms   necrosis and water-soaking     10.sup.7 cfu/ml                no symptoms   necrosis and water-soaking     10.sup.8 cfu/ml                necrosis      necrosis and water-soaking     ______________________________________

Example 7

Harpin-induced Resistance of Geranium (Pelargonium hortoriam) Against Bacterial Leaf Spot (Xanthamonas campestris pv. pelargonii)

This experiment was done with rooted cuttings of geranium growing in individual 4" or 6" pots in an artificial soil mix in a greenhouse. Two lower leaves on each plant were infiltrated with either 0.05M potassium phosphate buffer, pH 6.5 (control), or harpin or a suspension of Escherichia coli DH5(pCPP430) (the entire cloned hrp gene cluster of E. amylovora). Two to seven days following infiltration, all the plants were inoculated with a pure culture of the bacterial leaf spot pathogen, Xanthamonas campestris pv. pelargonii. A suspension of the bacteria (5×10⁶ cfu/ml) was atomized over both upper and lower leaf surfaces of the plants at low pressure. Each treatment was applied to two plants (designated "A" and "B" in Table 7). The plants were maintained in a closed chamber for 48 hours with supplemental misting supplied by cool-mist foggers. Then, the plants were maintained on the greenhouse bench subject to ambient humidity and temperature of 23° C. to 32° C. for 10 days before disease development was assessed.

                  TABLE 7     ______________________________________     Effect of harpin and the hrp gene cluster of     Erwinia amylovora on the development of bacterial leaf     spot of geranium.     Time between treatment and inoculation with     Xanthomonas campestris pv. pelargonii             7 Days 5 Days   4 Days  3 Days 2 days             Plant  Plant    Plant   Plant  Plant     Treatment A      B     A   B    A   B   A    B   A   B     ______________________________________     Buffer    3*     5     5   4    3   2   4    3   4   5     Harpin    0      0     0   0    0   0   1    0   0   0     DH5 (pcPP430)               0      0     NT  NT   0   0   0    1   1   0     ______________________________________      *Numbers in table are the number of leaves showing disease symptoms      (pronounced necrosis, chlorosis, or wilting) 10 days following      inoculation.

Example 8

Activity of several harpins in inducing resistance to Wildfire Disease caused by Pseudomonas syringae pv. tabaci

Tobacco plants (Nicotiana tabacum var. Xanthi) were grown in the greenhouse. At 4 weeks of age, harpin preparations were infiltrated into a single panel of two lower leaves of each plant. Twelve plants were treated with each harpin preparation, and three were treated with the same potassium phosphate buffer that was used to prepare the harpins. The hypersensitive necrosis developed within 24 hours in the panels of the leaves infiltrated with the harpin preparations, but not with buffer.

At 7, 10, 11, and 12 days after harpin treatment, all plants were inoculated with suspensions of 10⁴ to 10⁶ cells/ml of Pseudomonas syringae pv. tabaci by infiltrating panels on upper leaves. Plants were incubated in the greenhouse for 7 days before disease development was evaluated. The results are tabulated as follows in Table 8:

                  TABLE 8     ______________________________________            Days between treatment and inoculation     Harpin source              12        11        10      7     log  Inoc.!              4     5     6   4   5   6   4   5   6   4   5                                  6     ______________________________________     None (buffer)              +     +     ++  +   +   ++  +   +   ++  +   +                                  ++                                  P. syringae - - + - - + - - + - - +                                  E. - - + - - + - - + - - +                                  chrysanthemi                                  E. amylovora - - + - - - - - + - - +     ______________________________________      - = No symptoms,      + = Necrosis with yellow halo, typical of wildfire disease      ++ = Severe necrosis with yellow halo, typical of wildfire disease

The results indicate that the harpin preparations from the three bacteria are effective in inducing resistance to the wildfire pathogen. Plants treated with either harpin exhibited no symptoms with the two lower inoculum concentrations used. At the higher concentration, symptoms were more severe on buffer-treated plants than harpin-treated plants.

Example 9

Harpin induced resistance against the Late Blight disease caused by Phytophthora infestans.

The late blight pathogen affects potatoes and tomatoes primarily. It was responsible for the infamous Irish potato famine. The activity of harpin in inducing resistance to this pathogen was tested on tomato seedlings grown in the greenhouse. Three-week old seedlings (cultivar `Mama Mia`, about 6 to 8 inches high) were treated with harpin and subsequently inoculated with Phythophthora infestans. Two panels of a lower leaf of each plant were infiltrated with a solution of harpin, a suspension of Escherichia coli DH5(pCPP430), which produces and secretes harpin, or potassium phosphate buffer.

Two, three, or four days following infiltration, the plants were inoculated with a mycelial suspension of Phytophthora infestans. The strain U.S. 7 was used, which is highly virulent to tomato. The mycelial suspension was made by blending gently the contents of two barley-meal agar plates on and in which the fungus had grown for 2 weeks at 21° C. The suspension was brushed onto the top and undersides of one leaf per treated plant with an artist's broad paint brush.

The treated and inoculated plants were incubated in a specially constructed mist chamber designed to maintain a temperature of 20°-23° C. in the greenhouse, while maintaining high relative humidity. The moisture was provided by several cool-mist foggers operating at maximum rate on purified water. Disease incidence was evaluated 13 days following inoculation with Phytophthora infestans, and the results are tabulated in Table 9. Each treatment was applied to four individual plants.

                  TABLE 9     ______________________________________     Numbers of lesion of late blight that were     present on tomato leaves 13 days after inoculation.            Days between treatment and inoculation     Treatment              4           3           2     Plant    A     B     C   D   A   B   C   D   A   B   C                                  D     ______________________________________     Buffer   3     2     0   0   1   2   2   0   0   0   4                                  1                                  Harpin 0 0 1 0 0 0 0 1 2 1 0 0                                  DH5(pCPP430) 0 0 0 1 0 2 2 1 0 1 1 0     ______________________________________

Treatment with harpin reduced the number of lesions that developed on plants at all intervals between treatment and inoculation. The number of late blight lesions that developed also was reduced by prior treatment with DH5(pCPP430), which produces and secretes harpin.

Although the invention has been described in detail for the purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention which is defined by the following claims.

    __________________________________________________________________________     SEQUENCE LISTING     (1) GENERAL INFORMATION:     (iii) NUMBER OF SEQUENCES: 9     (2) INFORMATION FOR SEQ ID NO:1:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 338 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS:     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:     MetGlnIleThrIleLysAlaHisIleGlyGlyAspLeuGlyValSer     151015     GlyLeuGlyAlaGlnGlyLeuLysGlyLeuAsnSerAlaAlaSerSer     202530     LeuGlySerSerValAspLysLeuSerSerThrIleAspLysLeuThr     354045     SerAlaLeuThrSerMetMetPheGlyGlyAlaLeuAlaGlnGlyLeu     505560     GlyAlaSerSerLysGlyLeuGlyMetSerAsnGlnLeuGlyGlnSer     65707580     PheGlyAsnGlyAlaGlnGlyAlaSerAsnLeuLeuSerValProLys     859095     SerGlyGlyAspAlaLeuSerLysMetPheAspLysAlaLeuAspAsp     100105110     LeuLeuGlyHisAspThrValThrLysLeuThrAsnGlnSerAsnGln     115120125     LeuAlaAsnSerMetLeuAsnAlaSerGlnMetThrGlnGlyAsnMet     130135140     AsnAlaPheGlySerGlyValAsnAsnAlaLeuSerSerIleLeuGly     145150155160     AsnGlyLeuGlyGlnSerMetSerGlyPheSerGlnProSerLeuGly     165170175     AlaGlyGlyLeuGlnGlyLeuSerGlyAlaGlyAlaPheAsnGlnLeu     180185190     GlyAsnAlaIleGlyMetGlyValGlyGlnAsnAlaAlaLeuSerAla     195200205     LeuSerAsnValSerThrHisValAspGlyAsnAsnArgHisPheVal     210215220     AspLysGluAspArgGlyMetAlaLysGluIleGlyGlnPheMetAsp     225230235240     GlnTyrProGluIlePheGlyLysProGluTyrGlnLysAspGlyTrp     245250255     SerSerProLysThrAspAspLysSerTrpAlaLysAlaLeuSerLys     260265270     ProAspAspAspGlyMetThrGlyAlaSerMetAspLysPheArgGln     275280285     AlaMetGlyMetIleLysSerAlaValAlaGlyAspThrGlyAsnThr     290295300     AsnLeuAsnLeuArgGlyAlaGlyGlyAlaSerLeuGlyIleAspAla     305310315320     AlaValValGlyAspLysIleAlaAsnMetSerLeuGlyLysLeuAla     325330335     AsnAla     (2) INFORMATION FOR SEQ ID NO:2:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 2141 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: DNA (genomic)     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:     CGATTTTACCCGGGTGAACGTGCTATGACCGACAGCATCACGGTATTCGACACCGTTACG60     GCGTTTATGGCCGCGATGAACCGGCATCAGGCGGCGCGCTGGTCGCCGCAATCCGGCGTC120     GATCTGGTATTTCAGTTTGGGGACACCGGGCGTGAACTCATGATGCAGATTCAGCCGGGG180     CAGCAATATCCCGGCATGTTGCGCACGCTGCTCGCTCGTCGTTATCAGCAGGCGGCAGAG240     TGCGATGGCTGCCATCTGTGCCTGAACGGCAGCGATGTATTGATCCTCTGGTGGCCGCTG300     CCGTCGGATCCCGGCAGTTATCCGCAGGTGATCGAACGTTTGTTTGAACTGGCGGGAATG360     ACGTTGCCGTCGCTATCCATAGCACCGACGGCGCGTCCGCAGACAGGGAACGGACGCGCC420     CGATCATTAAGATAAAGGCGGCTTTTTTTATTGCAAAACGGTAACGGTGAGGAACCGTTT480     CACCGTCGGCGTCACTCAGTAACAAGTATCCATCATGATGCCTACATCGGGATCGGCGTG540     GGCATCCGTTGCAGATACTTTTGCGAACACCTGACATGAATGAGGAAACGAAATTATGCA600     AATTACGATCAAAGCGCACATCGGCGGTGATTTGGGCGTCTCCGGTCTGGGGCTGGGTGC660     TCAGGGACTGAAAGGACTGAATTCCGCGGCTTCATCGCTGGGTTCCAGCGTGGATAAACT720     GAGCAGCACCATCGATAAGTTGACCTCCGCGCTGACTTCGATGATGTTTGGCGGCGCGCT780     GGCGCAGGGGCTGGGCGCCAGCTCGAAGGGGCTGGGGATGAGCAATCAACTGGGCCAGTC840     TTTCGGCAATGGCGCGCAGGGTGCGAGCAACCTGCTATCCGTACCGAAATCCGGCGGCGA900     TGCGTTGTCAAAAATGTTTGATAAAGCGCTGGACGATCTGCTGGGTCATGACACCGTGAC960     CAAGCTGACTAACCAGAGCAACCAACTGGCTAATTCAATGCTGAACGCCAGCCAGATGAC1020     CCAGGGTAATATGAATGCGTTCGGCAGCGGTGTGAACAACGCACTGTCGTCCATTCTCGG1080     CAACGGTCTCGGCCAGTCGATGAGTGGCTTCTCTCAGCCTTCTCTGGGGGCAGGCGGCTT1140     GCAGGGCCTGAGCGGCGCGGGTGCATTCAACCAGTTGGGTAATGCCATCGGCATGGGCGT1200     GGGGCAGAATGCTGCGCTGAGTGCGTTGAGTAACGTCAGCACCCACGTAGACGGTAACAA1260     CCGCCACTTTGTAGATAAAGAAGATCGCGGCATGGCGAAAGAGATCGGCCAGTTTATGGA1320     TCAGTATCCGGAAATATTCGGTAAACCGGAATACCAGAAAGATGGCTGGAGTTCGCCGAA1380     GACGGACGACAAATCCTGGGCTAAAGCGCTGAGTAAACCGGATGATGACGGTATGACCGG1440     CGCCAGCATGGACAAATTCCGTCAGGCGATGGGTATGATCAAAAGCGCGGTGGCGGGTGA1500     TACCGGCAATACCAACCTGAACCTGCGTGGCGCGGGCGGTGCATCGCTGGGTATCGATGC1560     GGCTGTCGTCGGCGATAAAATAGCCAACATGTCGCTGGGTAAGCTGGCCAACGCCTGATA1620     ATCTGTGCTGGCCTGATAAAGCGGAAACGAAAAAAGAGACGGGGAAGCCTGTCTCTTTTC1680     TTATTATGCGGTTTATGCGGTTACCTGGACCGGTTAATCATCGTCATCGATCTGGTACAA1740     ACGCACATTTTCCCGTTCATTCGCGTCGTTACGCGCCACAATCGCGATGGCATCTTCCTC1800     GTCGCTCAGATTGCGCGGCTGATGGGGAACGCCGGGTGGAATATAGAGAAACTCGCCGGC1860     CAGATGGAGACACGTCTGCGATAAATCTGTGCCGTAACGTGTTTCTATCCGCCCCTTTAG1920     CAGATAGATTGCGGTTTCGTAATCAACATGGTAATGCGGTTCCGCCTGTGCGCCGGCCGG1980     GATCACCACAATATTCATAGAAAGCTGTCTTGCACCTACCGTATCGCGGGAGATACCGAC2040     AAAATAGGGCAGTTTTTGCGTGGTATCCGTGGGGTGTTCCGGCCTGACAATCTTGAGTTG2100     GTTCGTCATCATCTTTCTCCATCTGGGCGACCTGATCGGTT2141     (2) INFORMATION FOR SEQ ID NO:3:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 385 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS:     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:     MetSerLeuAsnThrSerGlyLeuGlyAlaSerThrMetGlnIleSer     151015     IleGlyGlyAlaGlyGlyAsnAsnGlyLeuLeuGlyThrSerArgGln     202530     AsnAlaGlyLeuGlyGlyAsnSerAlaLeuGlyLeuGlyGlyGlyAsn     354045     GlnAsnAspThrValAsnGlnLeuAlaGlyLeuLeuThrGlyMetMet     505560     MetMetMetSerMetMetGlyGlyGlyGlyLeuMetGlyGlyGlyLeu     65707580     GlyGlyGlyLeuGlyAsnGlyLeuGlyGlySerGlyGlyLeuGlyGlu     859095     GlyLeuSerAsnAlaLeuAsnAspMetLeuGlyGlySerLeuAsnThr     100105110     LeuGlySerLysGlyGlyAsnAsnThrThrSerThrThrAsnSerPro     115120125     LeuAspGlnAlaLeuGlyIleAsnSerThrSerGlnAsnAspAspSer     130135140     ThrSerGlyThrAspSerThrSerAspSerSerAspProMetGlnGln     145150155160     LeuLeuLysMetPheSerGluIleMetGlnSerLeuPheGlyAspGly     165170175     GlnAspGlyThrGlnGlySerSerSerGlyGlyLysGlnProThrGlu     180185190     GlyGluGlnAsnAlaTyrLysLysGlyValThrAspAlaLeuSerGly     195200205     LeuMetGlyAsnGlyLeuSerGlnLeuLeuGlyAsnGlyGlyLeuGly     210215220     GlyGlyGlnGlyGlyAsnAlaGlyThrGlyLeuAspGlySerSerLeu     225230235240     GlyGlyLysGlyLeuGlnAsnLeuSerGlyProValAspTyrGlnGln     245250255     LeuGlyAsnAlaValGlyThrGlyIleGlyMetLysAlaGlyIleGln     260265270     AlaLeuAsnAspIleGlyThrHisArgHisSerSerThrArgSerPhe     275280285     ValAsnLysGlyAspArgAlaMetAlaLysGluIleGlyGlnPheMet     290295300     AspGlnTyrProGluValPheGlyLysProGlnTyrGlnLysGlyPro     305310315320     GlyGlnGluValLysThrAspAspLysSerTrpAlaLysAlaLeuSer     325330335     LysProAspAspAspGlyMetThrProAlaSerMetGluGlnPheAsn     340345350     LysAlaLysGlyMetIleLysArgProMetAlaGlyAspThrGlyAsn     355360365     GlyAsnLeuGlnHisAlaValProValValLeuArgTrpValLeuMet     370375380     Pro     385     (2) INFORMATION FOR SEQ ID NO:4:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 1158 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: DNA (genomic)     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:     ATGAGTCTGAATACAAGTGGGCTGGGAGCGTCAACGATGCAAATTTCTATCGGCGGTGCG60     GGCGGAAATAACGGGTTGCTGGGTACCAGTCGCCAGAATGCTGGGTTGGGTGGCAATTCT120     GCACTGGGGCTGGGCGGCGGTAATCAAAATGATACCGTCAATCAGCTGGCTGGCTTACTC180     ACCGGCATGATGATGATGATGAGCATGATGGGCGGTGGTGGGCTGATGGGCGGTGGCTTA240     GGCGGTGGCTTAGGTAATGGCTTGGGTGGCTCAGGTGGCCTGGGCGAAGGACTGTCGAAC300     GCGCTGAACGATATGTTAGGCGGTTCGCTGAACACGCTGGGCTCGAAAGGCGGCAACAAT360     ACCACTTCAACAACAAATTCCCCGCTGGACCAGGCGCTGGGTATTAACTCAACGTCCCAA420     AACGACGATTCCACCTCCGGCACAGATTCCACCTCAGACTCCAGCGACCCGATGCAGCAG480     CTGCTGAAGATGTTCAGCGAGATAATGCAAAGCCTGTTTGGTGATGGGCAAGATGGCACC540     CAGGGCAGTTCCTCTGGGGGCAAGCAGCCGACCGAAGGCGAGCAGAACGCCTATAAAAAA600     GGAGTCACTGATGCGCTGTCGGGCCTGATGGGTAATGGTCTGAGCCAGCTCCTTGGCAAC660     GGGGGACTGGGAGGTGGTCAGGGCGGTAATGCTGGCACGGGTCTTGACGGTTCGTCGCTG720     GGCGGCAAAGGGCTGCAAAACCTGAGCGGGCCGGTGGACTACCAGCAGTTAGGTAACGCC780     GTGGGTACCGGTATCGGTATGAAAGCGGGCATTCAGGCGCTGAATGATATCGGTACGCAC840     AGGCACAGTTCAACCCGTTCTTTCGTCAATAAAGGCGATCGGGCGATGGCGAAGGAAATC900     GGTCAGTTCATGGACCAGTATCCTGAGGTGTTTGGCAAGCCGCAGTACCAGAAAGGCCCG960     GGTCAGGAGGTGAAAACCGATGACAAATCATGGGCAAAAGCACTGAGCAAGCCAGATGAC1020     GACGGAATGACACCAGCCAGTATGGAGCAGTTCAACAAAGCCAAGGGCATGATCAAAAGG1080     CCCATGGCGGGTGATACCGGCAACGGCAACCTGCAGCACGCGGTGCCGGTGGTTCTTCGC1140     TGGGTATTGATGCCATGA1158     (2) INFORMATION FOR SEQ ID NO:5:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 341 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS:     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:     MetGlnSerLeuSerLeuAsnSerSerSerLeuGlnThrProAlaMet     151015     AlaLeuValLeuValArgProGluAlaGluThrThrGlySerThrSer     202530     SerLysAlaLeuGlnGluValValValLysLeuAlaGluGluLeuMet     354045     ArgAsnGlyGlnLeuAspAspSerSerProLeuGlyLysLeuLeuAla     505560     LysSerMetAlaAlaAspGlyLysAlaGlyGlyGlyIleGluAspVal     65707580     IleAlaAlaLeuAspLysLeuIleHisGluLysLeuGlyAspAsnPhe     859095     GlyAlaSerAlaAspSerAlaSerGlyThrGlyGlnGlnAspLeuMet     100105110     ThrGlnValLeuAsnGlyLeuAlaLysSerMetLeuAspAspLeuLeu     115120125     ThrLysGlnAspGlyGlyThrSerPheSerGluAspAspMetProMet     130135140     LeuAsnLysIleAlaGlnPheMetAspAspAsnProAlaGlnPhePro     145150155160     LysProAspSerGlySerTrpValAsnGluLeuLysGluAspAsnPhe     165170175     LeuAspGlyAspGluThrAlaAlaPheArgSerAlaLeuAspIleIle     180185190     GlyGlnGlnLeuGlyAsnGlnGlnSerAspAlaGlySerLeuAlaGly     195200205     ThrGlyGlyGlyLeuGlyThrProSerSerPheSerAsnAsnSerSer     210215220     ValMetGlyAspProLeuIleAspAlaAsnThrGlyProGlyAspSer     225230235240     GlyAsnThrArgGlyGluAlaGlyGlnLeuIleGlyGluLeuIleAsp     245250255     ArgGlyLeuGlnSerValLeuAlaGlyGlyGlyLeuGlyThrProVal     260265270     AsnThrProGlnThrGlyThrSerAlaAsnGlyGlyGlnSerAlaGln     275280285     AspLeuAspGlnLeuLeuGlyGlyLeuLeuLeuLysGlyLeuGluAla     290295300     ThrLeuLysAspAlaGlyGlnThrGlyThrAspValGlnSerSerAla     305310315320     AlaGlnIleAlaThrLeuLeuValSerThrLeuLeuGlnGlyThrArg     325330335     AsnGlnAlaAlaAla     340     (2) INFORMATION FOR SEQ ID NO:6:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 1026 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: DNA (genomic)     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:     ATGCAGAGTCTCAGTCTTAACAGCAGCTCGCTGCAAACCCCGGCAATGGCCCTTGTCCTG60     GTACGTCCTGAAGCCGAGACGACTGGCAGTACGTCGAGCAAGGCGCTTCAGGAAGTTGTC120     GTGAAGCTGGCCGAGGAACTGATGCGCAATGGTCAACTCGACGACAGCTCGCCATTGGGA180     AAACTGTTGGCCAAGTCGATGGCCGCAGATGGCAAGGCGGGCGGCGGTATTGAGGATGTC240     ATCGCTGCGCTGGACAAGCTGATCCATGAAAAGCTCGGTGACAACTTCGGCGCGTCTGCG300     GACAGCGCCTCGGGTACCGGACAGCAGGACCTGATGACTCAGGTGCTCAATGGCCTGGCC360     AAGTCGATGCTCGATGATCTTCTGACCAAGCAGGATGGCGGGACAAGCTTCTCCGAAGAC420     GATATGCCGATGCTGAACAAGATCGCGCAGTTCATGGATGACAATCCCGCACAGTTTCCC480     AAGCCGGACTCGGGCTCCTGGGTGAACGAACTCAAGGAAGACAACTTCCTTGATGGCGAC540     GAAACGGCTGCGTTCCGTTCGGCACTCGACATCATTGGCCAGCAACTGGGTAATCAGCAG600     AGTGACGCTGGCAGTCTGGCAGGGACGGGTGGAGGTCTGGGCACTCCGAGCAGTTTTTCC660     AACAACTCGTCCGTGATGGGTGATCCGCTGATCGACGCCAATACCGGTCCCGGTGACAGC720     GGCAATACCCGTGGTGAAGCGGGGCAACTGATCGGCGAGCTTATCGACCGTGGCCTGCAA780     TCGGTATTGGCCGGTGGTGGACTGGGCACACCCGTAAACACCCCGCAGACCGGTACGTCG840     GCGAATGGCGGACAGTCCGCTCAGGATCTTGATCAGTTGCTGGGCGGCTTGCTGCTCAAG900     GGCCTGGAGGCAACGCTCAAGGATGCCGGGCAAACAGGCACCGACGTGCAGTCGAGCGCT960     GCGCAAATCGCCACCTTGCTGGTCAGTACGCTGCTGCAAGGCACCCGCAATCAGGCTGCA1020     GCCTGA1026     (2) INFORMATION FOR SEQ ID NO:7:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 344 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS:     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:     MetSerValGlyAsnIleGlnSerProSerAsnLeuProGlyLeuGln     151015     AsnLeuAsnLeuAsnThrAsnThrAsnSerGlnGlnSerGlyGlnSer     202530     ValGlnAspLeuIleLysGlnValGluLysAspIleLeuAsnIleIle     354045     AlaAlaLeuValGlnLysAlaAlaGlnSerAlaGlyGlyAsnThrGly     505560     AsnThrGlyAsnAlaProAlaLysAspGlyAsnAlaAsnAlaGlyAla     65707580     AsnAspProSerLysAsnAspProSerLysSerGlnAlaProGlnSer     859095     AlaAsnLysThrGlyAsnValAspAspAlaAsnAsnGlnAspProMet     100105110     GlnAlaLeuMetGlnLeuLeuGluAspLeuValLysLeuLeuLysAla     115120125     AlaLeuHisMetGlnGlnProGlyGlyAsnAspLysGlyAsnGlyVal     130135140     GlyGlyAlaAsnGlyAlaLysGlyAlaGlyGlyGlnGlyGlyLeuAla     145150155160     GluAlaLeuGlnGluIleGluGlnIleLeuAlaGlnLeuGlyGlyGly     165170175     GlyAlaGlyAlaGlyGlyAlaGlyGlyGlyValGlyGlyAlaGlyGly     180185190     AlaAspGlyGlySerGlyAlaGlyGlyAlaGlyGlyAlaAsnGlyAla     195200205     AspGlyGlyAsnGlyValAsnGlyAsnGlnAlaAsnGlyProGlnAsn     210215220     AlaGlyAspValAsnGlyAlaAsnGlyAlaAspAspGlySerGluAsp     225230235240     GlnGlyGlyLeuThrGlyValLeuGlnLysLeuMetLysIleLeuAsn     245250255     AlaLeuValGlnMetMetGlnGlnGlyGlyLeuGlyGlyGlyAsnGln     260265270     AlaGlnGlyGlySerLysGlyAlaGlyAsnAlaSerProAlaSerGly     275280285     AlaAsnProGlyAlaAsnGlnProGlySerAlaAspAspGlnSerSer     290295300     GlyGlnAsnAsnLeuGlnSerGlnIleMetAspValValLysGluVal     305310315320     ValGlnIleLeuGlnGlnMetLeuAlaAlaGlnAsnGlyGlySerGln     325330335     GlnSerThrSerThrGlnProMet     340     (2) INFORMATION FOR SEQ ID NO:8:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 1035 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: DNA (genomic)     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:     ATGTCAGTCGGAAACATCCAGAGCCCGTCGAACCTCCCGGGTCTGCAGAACCTGAACCTC60     AACACCAACACCAACAGCCAGCAATCGGGCCAGTCCGTGCAAGACCTGATCAAGCAGGTC120     GAGAAGGACATCCTCAACATCATCGCAGCCCTCGTGCAGAAGGCCGCACAGTCGGCGGGC180     GGCAACACCGGTAACACCGGCAACGCGCCGGCGAAGGACGGCAATGCCAACGCGGGCGCC240     AACGACCCGAGCAAGAACGACCCGAGCAAGAGCCAGGCTCCGCAGTCGGCCAACAAGACC300     GGCAACGTCGACGACGCCAACAACCAGGATCCGATGCAAGCGCTGATGCAGCTGCTGGAA360     GACCTGGTGAAGCTGCTGAAGGCGGCCCTGCACATGCAGCAGCCCGGCGGCAATGACAAG420     GGCAACGGCGTGGGCGGTGCCAACGGCGCCAAGGGTGCCGGCGGCCAGGGCGGCCTGGCC480     GAAGCGCTGCAGGAGATCGAGCAGATCCTCGCCCAGCTCGGCGGCGGCGGTGCTGGCGCC540     GGCGGCGCGGGTGGCGGTGTCGGCGGTGCTGGTGGCGCGGATGGCGGCTCCGGTGCGGGT600     GGCGCAGGCGGTGCGAACGGCGCCGACGGCGGCAATGGCGTGAACGGCAACCAGGCGAAC660     GGCCCGCAGAACGCAGGCGATGTCAACGGTGCCAACGGCGCGGATGACGGCAGCGAAGAC720     CAGGGCGGCCTCACCGGCGTGCTGCAAAAGCTGATGAAGATCCTGAACGCGCTGGTGCAG780     ATGATGCAGCAAGGCGGCCTCGGCGGCGGCAACCAGGCGCAGGGCGGCTCGAAGGGTGCC840     GGCAACGCCTCGCCGGCTTCCGGCGCGAACCCGGGCGCGAACCAGCCCGGTTCGGCGGAT900     GATCAATCGTCCGGCCAGAACAATCTGCAATCCCAGATCATGGATGTGGTGAAGGAGGTC960     GTCCAGATCCTGCAGCAGATGCTGGCGGCGCAGAACGGCGGCAGCCAGCAGTCCACCTCG1020     ACGCAGCCGATGTAA1035     (2) INFORMATION FOR SEQ ID NO:9:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 26 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS:     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:     ThrLeuIleGluLeuMetIleValValAlaIleIleAlaIleLeuAla     151015     AlaIleAlaLeuProAlaTyrGlnAspTyr     2025     __________________________________________________________________________ 

What is claimed:
 1. A pathogen-resistant plant to which a hypersensitive response eliciting bacterium, which does not cause disease in that plant, or a hypersensitive response eliciting polypeptide or protein has been externally applied, wherein the hypersensitive response eliciting polypetide or protein corresponds to that derived from a pathogen selected from the group consisting of Erwinia amylovora, Erwinia chrysanthemi, Pseudomonas syringae, Pseudomonas solancearum, Xanthamonas campestris, and mixtures thereof.
 2. A pathogen-resistant plant according to claim 1, wherein the hypersensitive response eliciting polypeptide or protein is in isolated form.
 3. A pathogen-resistant plant according to claim 1, wherein the plant cells are in contact with bacteria which do not cause disease and are transformed with a gene encoding the hypersensitive response eliciting polypeptide or protein.
 4. A pathogen-resistant plant according to claim 1, wherein the plant cells are in contact with bacteria which do not cause disease in the plant, but do cause disease in other plant species, and contain a gene encoding the hypersensitive response eliciting polypeptide or protein.
 5. A pathogen-resistant plant according to claim 2, wherein the hypersensitive response eliciting polypeptide or protein corresponds to that derived from Erwinia chrysanthemi.
 6. A pathogen-resistant plant according to claim 5, wherein the hypersensitive response eliciting polypeptide or protein has an amino acid sequence corresponding to SEQ. ID. No.
 1. 7. A pathogen-resistant plant according to claim 2, wherein the hypersensitive response eliciting polypeptide or protein corresponds to that derived from Erwinia amylovora.
 8. A pathogen-resistant plant according to claim 7, wherein the hypersensitive response eliciting polypeptide or protein has an amino acid sequence corresponding to SEQ. ID. No.
 3. 9. A pathogen-resistant plant according to claim 2, wherein the hypersensitive response eliciting polypeptide or protein corresponds to that derived from Pseudomonas syringae.
 10. A pathogen-resistant plant according to claim 9, wherein the hypersensitive response eliciting polypeptide or protein has an amino acid sequence corresponding to SEQ. ID. No.
 5. 11. A pathogen-resistant plant according to claim 2, wherein the hypersensitive response eliciting polypeptide or protein corresponds to that derived from Pseudomonas solanacearum.
 12. A pathogen-resistant plant according to claim 11, wherein the hypersensitive response eliciting polypeptide or protein has an amino acid sequence corresponding to SEQ. ID. No.
 7. 13. A pathogen-resistant plant according to claim 2, wherein the hypersensitive response eliciting polypeptide or protein corresponds to that derived from Xanthomonas campestris.
 14. A pathogen-resistant plant according to claim 13, wherein the hypersensitive response eliciting polypeptide or protein has an amino acid sequence corresponding to SEQ. ID. No.
 9. 15. A pathogen-resistant plant according to claim 2, wherein the plant is selected from the group consisting of dicots and monocots.
 16. A pathogen-resistant plant according to claim 15, wherein the plant is selected from the group consisting of rice, wheat, barley, rye, cotton, sunflower, peanut, potato, sweet potato, bean, pea, chicory, lettuce, endive, cabbage, cauliflower, broccoli, turnip, radish, spinach, onion, garlic, eggplant, pepper, celery, carrot, squash, pumpkin, zucchini, cucumber, apple, pear, melon, strawberry, grape, raspberry, pineapple, soybean, tobacco, tomato, sorghum, and sugarcane.
 17. A pathogen-resistant plant according to claim 15, wherein the plant is selected from the group consisting of Arabidopsis thaliana, Saintpaulia, petunia, pelangonium, poinsettia, chrysanthemum, carnation, and zinnia.
 18. A pathogen-resistant plant according to claim 2, wherein the pathogen to which the plant is resistant is selected from the group consisting of a virus, bacterium, fungus, and combinations thereof. 